Method of Quality Inspection of a Joint of a Power Cable

Abstract

A method of performing a quality inspection of a vulcanized joint of a power cable during manufacturing of the vulcanized joint, the method comprising: a) obtaining, from a laser scanner, measurements of an outer surface of an inner semiconducting layer provided over a conductor joint which joints conductors of two power cable sections, and of a transition area between the outer surface and outer surfaces of a respective inner semiconducting layer of the two power cable sections, b) obtaining, from a laser scanner, measurements of an outer surface of a tapering section of an insulation layer arranged around a respective one of the inner semiconducting layers of the two cable sections, c) processing the measurements obtained in step a) and in step b), the processing involving generating one or a respective 3-d model of the outer surfaces and evaluating an outer surface quality of the outer surfaces based on the one or more 3-d models, d) presenting a conclusion regarding surface quality based on the evaluation, e) obtaining, from a laser scanner, measurements of an outer surface of a joint insulation arranged around the inner semiconducting layer that is provided over the conductor joint, the joint insulation having been provided over the inner semiconducting layer provided around the conductor joint after step d), and f) processing measurements obtained from the laser scanner in step e), the processing involving determining an insulation thickness or an outer diameter of the joint insulation, and g 1 ) presenting the insulation thickness or outer diameter, and/or, g 2 ) evaluating the insulation thickness or outer diameter, and presenting a conclusion regarding the insultation thickness or outer diameter based on the comparison.

1 . A method of performing a quality inspection of a vulcanized joint of a power cable during manufacturing of the vulcanized joint, the method comprising:
 a) obtaining, from a laser scanner, measurements of an outer surface of an inner semiconducting layer provided over a conductor joint which joints conductors of two power cable sections, and of a transition area between the outer surface and outer surfaces of a respective inner semiconducting layer of the two power cable sections,   b) obtaining, from a laser scanner, measurements of an outer surface of a tapering section of an insulation layer arranged around a respective one of the inner semiconducting layers of the two cable sections,   c) processing the measurements obtained in step a) and in step b), the processing involving generating one or a respective 3D model of the outer surfaces and evaluating an outer surface quality of the outer surfaces based on the one or more 3D models,   d) presenting a conclusion regarding surface quality based on the evaluation,   e) obtaining, from a laser scanner, measurements of an outer surface of a joint insulation arranged around the inner semiconducting layer that is provided over the conductor joint, the joint insulation having been provided over the inner semiconducting layer provided around the conductor joint after step d), and   f) processing the measurements obtained from the laser scanner in step e), the processing involving determining an insulation thickness or an outer diameter of the joint insulation, and   g 1 ) presenting the insulation thickness or outer diameter, and/or,   g 2 ) evaluating the insulation thickness or outer diameter, and presenting a conclusion regarding the insultation thickness or outer diameter based on the comparison.   
     
     
         2 . The method as claimed in  claim 1 , wherein step f) involves generating a 3D model of the outer surface of the joint insulation. 
     
     
         3 . The method as claimed in  claim 1 , wherein the evaluating in step c) involves assessing roundness and surface texture of the outer surfaces. 
     
     
         4 . The method as claimed in  claim 1 , wherein the evaluating in step c) involves comparing each 3D model with a respective reference 3D model. 
     
     
         5 . The method as claimed in  claim 1 , wherein the evaluating in step g 2 ) involves comparing the insulation thickness or the outer diameter with a reference. 
     
     
         6 . The method as claimed in  claim 5 , wherein the reference is a 3D model of the joint insulation. 
     
     
         7 . The method as claimed in  claim 1 , wherein the laser scanner is a 3D laser scanner. 
     
     
         8 . A quality inspection system comprising:
 processing circuitry,   a laser scanner configured to send measurements to the processing circuitry, and   a storage medium having computer code which when executed by the processing circuitry causes the quality inspection system to carry out the method of performing a quality inspection of a vulcanized joint of a power cable during manufacturing of the vulcanized joint, the method including:   a) obtaining, from a laser scanner, measurements of an outer surface of an inner semiconducting layer provided over a conductor joint which joints conductors of two power cable sections, and of a transition area between the outer surface and outer surfaces of a respective inner semiconducting layer of the two power cable sections,   b) obtaining, from a laser scanner, measurements of an outer surface of a tapering section of an insulation layer arranged around a respective one of the inner semiconducting layers of the two cable sections,   c) processing the measurements obtained in step a) and in step b), the processing involving generating one or a respective 3D model of the outer surfaces and evaluating an outer surface quality of the outer surfaces based on the one or more 3D models,   d) presenting a conclusion regarding surface quality based on the evaluation,   e) obtaining, from a laser scanner, measurements of an outer surface of a joint insulation arranged around the inner semiconducting layer that is provided over the conductor joint, the joint insulation having been provided over the inner semiconducting layer provided around the conductor joint after step d), and   f) processing the measurements obtained from the laser scanner in step e), the processing involving determining an insulation thickness or an outer diameter of the joint insulation, and   g 1 ) presenting the insulation thickness or outer diameter, and/or,   g 2 ) evaluating the insulation thickness or outer diameter, and presenting a conclusion regarding the insulation thickness or outer diameter based on the comparison.   
     
     
         9 . A method of making a vulcanized joint of a power cable utilising the quality inspection system comprising:
 A) making a conductor joint between two conductor ends of respective power cable lengths, to form a single power cable with two power cable sections separated by the conductor joint,   B) making a respective insulation layer of the two power cable sections tapering,   C) providing an inner semiconducting layer around the conductor joint, the inner semiconducting layer contacting respective inner semiconducting layers of the power cable sections,   D) making a quality inspection of the outer surface of the inner semiconducting layers and of the tapering outer surfaces of the insulation layers of the two power cable sections using the quality inspection system,   wherein if the outcome of the quality inspection is a fail, the method includes: E) mechanically processing the outer surface(s) of the inner semiconducting layer(s) and/or the tapering outer surfaces, and repeating step D),   wherein if the outcome of the quality inspection is a pass, the method includes: F) making a joint insulation over the inner semiconducting layer provided around the conductor joint, the joint insulation contacting the tapering outer surfaces,   G) making a quality inspection of the joint insulation using the quality inspection system to determine an outer diameter or insulation thickness of the joint insulation,   wherein if the outcome of the quality inspection in step G) is a fail, the method includes: H) mechanically processing the outer surface of the joint insulation, and repeating steps G) and H) until the outcome of the quality inspection in step G) is a pass.   
     
     
         10 . The method as claimed in  claim 2 , wherein the evaluating in step c) involves assessing roundness and surface texture of the outer surfaces. 
     
     
         11 . The method as claimed in  claim 2 , wherein the evaluating in step c) involves comparing each 3D model with a respective reference 3D model. 
     
     
         12 . The method as claimed in  claim 2 , wherein the evaluating in step g 2 ) involves comparing the insulation thickness or the outer diameter with a reference. 
     
     
         13 . The method as claimed in  claim 2 , wherein the laser scanner is a 3D laser scanner.